AFM CHARACTERIZATION OF TA-BASED DIFFUSION-BARRIERS FOR USE IN FUTURESEMICONDUCTOR METALLIZATION

In this paper the investigation of r.f.-sputter-deposited Ta, Ta-N and Ta-N-O thin films is presented. Using atomic force microscopy in comb ination with sheet resistance measurements, Anger electron spectroscop y and x-ray diffraction, the thin film properties and microstructure a re examined. Two crystalline modifications of Ta (tetragonal beta-Ta a nd bcc alpha-Ta) are reported. By incorporation of nitrogen and/or oxy gen into the Ta films, nanocrystalline and quasi-amorphous structures can be achieved. Finally, the usefulness of the films as diffusion bar riers in Cu-based metallization systems is described. (C) 1997 by John Wiley & Sons, Ltd.